The long-term objective of this competitive renewal is to evaluate the functional role of chemokine and chemokine receptors in contributing to neurologic disease and repair following infection with a neurotropic murine coronavirus, mouse hepatitis virus (MHV). Infection of susceptible mice with MHV reproducibly results in an acute encephalomyelitis followed by a chronic demyelinating disease characterized clinically by ascending hind-limb paralysis and histologically by mononuclear cell infiltration into the central nervous system (CNS) accompanied by white matter destruction. Due to the similarities in clinical and histologic disease between MHV-induced demyelination and the human demyelinating disease multiple sclerosis (MS), the MHV system is considered an excellent model in which to study the underlying pathological mechanisms contributing to human demyelinating diseases such as MS. Similar to MS, both T cells and macrophages are thought to be important in contributing to white matter destruction. In addition, chemokine and chemokine receptors are expressed within the CNS of MS patients as well as MHV- infected mice indicating a prominent role in the pathogenesis of disease. Indeed, during the previous funding periods (initiated in 2000), we have defined functional roles for chemokines and chemokine receptors in regulating neuroinflammation that is involved in both host defense and demyelination in response to MHV infection by regulating lymphocyte and macrophage infiltration. The present proposal builds upon our previous work and offers the opportunity to define the functional role of chemokines and chemokine receptors in i) protecting oligodendrocytes (the myelin-producing cell of the CNS) from damage/death and ii) regulating the biology of engrafted neural progenitor cells e.g. positional migration and proliferation which contributes to axonal remyelination. Together, these studies will extend our current understanding of how chemokines and their receptors participate in protection and repair. Further, the data obtained from these experiments will identify potentially novel therapeutic approaches for treatment of MS as well as other human demyelinating diseases.